Suspicious Microsoft Office Child Process

calendar Aug 12, 2024 · attack.defense-evasion attack.execution attack.t1047 attack.t1204.002 attack.t1218.010  ·
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Detects a suspicious process spawning from one of the Microsoft Office suite products (Word, Excel, PowerPoint, Publisher, Visio, etc.)

Sigma rule (View on GitHub)

  1title: Suspicious Microsoft Office Child Process
  2id: 438025f9-5856-4663-83f7-52f878a70a50
  3related:
  4    - id: c27515df-97a9-4162-8a60-dc0eeb51b775 # Speicifc OneNote rule due to its recent usage in phishing attacks
  5      type: derived
  6    - id: e1693bc8-7168-4eab-8718-cdcaa68a1738
  7      type: derived
  8    - id: 23daeb52-e6eb-493c-8607-c4f0246cb7d8
  9      type: obsolete
 10    - id: 518643ba-7d9c-4fa5-9f37-baed36059f6a
 11      type: obsolete
 12    - id: 04f5363a-6bca-42ff-be70-0d28bf629ead
 13      type: obsolete
 14status: test
 15description: Detects a suspicious process spawning from one of the Microsoft Office suite products (Word, Excel, PowerPoint, Publisher, Visio, etc.)
 16references:
 17    - https://www.hybrid-analysis.com/sample/465aabe132ccb949e75b8ab9c5bda36d80cf2fd503d52b8bad54e295f28bbc21?environmentId=100
 18    - https://mgreen27.github.io/posts/2018/04/02/DownloadCradle.html
 19    - https://thedfirreport.com/2021/03/29/sodinokibi-aka-revil-ransomware/
 20    - https://doublepulsar.com/follina-a-microsoft-office-code-execution-vulnerability-1a47fce5629e
 21    - https://github.com/vadim-hunter/Detection-Ideas-Rules/blob/02bcbfc2bfb8b4da601bb30de0344ae453aa1afe/Threat%20Intelligence/The%20DFIR%20Report/20210329_Sodinokibi_(aka_REvil)_Ransomware.yaml
 22    - https://github.com/splunk/security_content/blob/develop/detections/endpoint/office_spawning_control.yml
 23    - https://twitter.com/andythevariable/status/1576953781581144064?s=20&t=QiJILvK4ZiBdR8RJe24u-A
 24    - https://www.elastic.co/security-labs/exploring-the-ref2731-intrusion-set
 25    - https://github.com/elastic/detection-rules/blob/c76a39796972ecde44cb1da6df47f1b6562c9770/rules/windows/defense_evasion_execution_msbuild_started_by_office_app.toml
 26    - https://www.vmray.com/analyses/2d2fa29185ad/report/overview.html
 27    - https://app.any.run/tasks/c903e9c8-0350-440c-8688-3881b556b8e0/
 28author: Florian Roth (Nextron Systems), Markus Neis, FPT.EagleEye Team, Vadim Khrykov, Cyb3rEng, Michael Haag, Christopher Peacock @securepeacock, @scythe_io
 29date: 2018-04-06
 30modified: 2023-04-24
 31tags:
 32    - attack.defense-evasion
 33    - attack.execution
 34    - attack.t1047
 35    - attack.t1204.002
 36    - attack.t1218.010
 37logsource:
 38    category: process_creation
 39    product: windows
 40detection:
 41    selection_parent:
 42        ParentImage|endswith:
 43            - '\EQNEDT32.EXE'
 44            - '\EXCEL.EXE'
 45            - '\MSACCESS.EXE'
 46            - '\MSPUB.exe'
 47            - '\ONENOTE.EXE'
 48            - '\POWERPNT.exe'
 49            - '\VISIO.exe'
 50            - '\WINWORD.EXE'
 51            - '\wordpad.exe'
 52            - '\wordview.exe'
 53    selection_child_processes:
 54        - OriginalFileName:
 55              - 'bitsadmin.exe'
 56              - 'CertOC.exe'
 57              - 'CertUtil.exe'
 58              - 'Cmd.Exe'
 59              - 'CMSTP.EXE'
 60              - 'cscript.exe'
 61              - 'curl.exe'
 62              - 'HH.exe'
 63              - 'IEExec.exe'
 64              - 'InstallUtil.exe'
 65              - 'javaw.exe'
 66              - 'Microsoft.Workflow.Compiler.exe'
 67              - 'msdt.exe'
 68              - 'MSHTA.EXE'
 69              - 'msiexec.exe'
 70              - 'Msxsl.exe'
 71              - 'odbcconf.exe'
 72              - 'pcalua.exe'
 73              - 'PowerShell.EXE'
 74              - 'RegAsm.exe'
 75              - 'RegSvcs.exe'
 76              - 'REGSVR32.exe'
 77              - 'RUNDLL32.exe'
 78              - 'schtasks.exe'
 79              - 'ScriptRunner.exe'
 80              - 'wmic.exe'
 81              - 'WorkFolders.exe'
 82              - 'wscript.exe'
 83        - Image|endswith:
 84              - '\AppVLP.exe'
 85              - '\bash.exe'
 86              - '\bitsadmin.exe'
 87              - '\certoc.exe'
 88              - '\certutil.exe'
 89              - '\cmd.exe'
 90              - '\cmstp.exe'
 91              - '\control.exe'
 92              - '\cscript.exe'
 93              - '\curl.exe'
 94              - '\forfiles.exe'
 95              - '\hh.exe'
 96              - '\ieexec.exe'
 97              - '\installutil.exe'
 98              - '\javaw.exe'
 99              - '\mftrace.exe'
100              - '\Microsoft.Workflow.Compiler.exe'
101              - '\msbuild.exe'
102              - '\msdt.exe'
103              - '\mshta.exe'
104              - '\msidb.exe'
105              - '\msiexec.exe'
106              - '\msxsl.exe'
107              - '\odbcconf.exe'
108              - '\pcalua.exe'
109              - '\powershell.exe'
110              - '\pwsh.exe'
111              - '\regasm.exe'
112              - '\regsvcs.exe'
113              - '\regsvr32.exe'
114              - '\rundll32.exe'
115              - '\schtasks.exe'
116              - '\scrcons.exe'
117              - '\scriptrunner.exe'
118              - '\sh.exe'
119              - '\svchost.exe'
120              - '\verclsid.exe'
121              - '\wmic.exe'
122              - '\workfolders.exe'
123              - '\wscript.exe'
124    selection_child_susp_paths: # Idea: Laiali Kazalbach, Mohamed Elsayed (#4142)
125        Image|contains:
126            - '\AppData\'
127            - '\Users\Public\'
128            - '\ProgramData\'
129            - '\Windows\Tasks\'
130            - '\Windows\Temp\'
131            - '\Windows\System32\Tasks\'
132    condition: selection_parent and 1 of selection_child_*
133falsepositives:
134    - Unknown
135level: high

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